Case Study; Large scale treatment of London site using ORC Advanced

1.
Figure 1. Direct Push Injection of ORC Advanced®
Remedial works at the Former Lama Petroleum site were undertaken in late 2008 as part of the ongoing
redevelopment of the Fresh Wharf Estate in Barking. The site was to be developed for light industrial use,
however, historical oil mixing handling and storage activities performed on the site had resulted in TPH and
PAH contamination in the groundwater.
Site investigation works suggested the presence of
an approximately 1,000m2
source area in the
northwestern portion of the site, as well as a
downgradient plume area, estimated to be in the
region of 6,000m2
extending toward the
Handtrough Creek. Phase separated hydrocarbons
were detected in the source area where the
former above ground storage tanks had been
located prior to decommissioning circa 2003. In
the down gradient plume area the maximum
dissolved phase TPH concentration was 1,100μg/L
(Monitoring Well BH102) adjacent to Handtrough
Creek.
Remedial Strategy
The remedial objective was to reduce dissolved phase concentrations of Total TPH and PAH in groundwater
to the agreed remedial target level of 110μg/L, within 12 months of treatment. A trigger level for further
remediation was set at 200μg/L, equating to an 80% contaminant concentration reduction within 42 weeks
post treatment. If the trigger TPH
concentration was not achieved within 42
weeks after treatment, further options would
be undertaken.
The original assessment of remedial options
identified that a combination of Pump and
Treat (P&T) to target free product in the source
area and ORC Advanced® treatment in the
groundwater plume would represent the most
time‐efficient and cost‐effective remedial
solution for the site. However, trial pits
advanced in the source area during site
clearance works determined that free product
was not present in the groundwater, but was
present in discrete bands within the
unsaturated made ground. Following this
observation, excavation to remove the most
impacted soils in the source area was
determined to be the most suitable approach
and P&T was discarded as an option.
Table 1. Subsurface Details
Soil Type Sand
Depth to Groundwater 3m
Treatment Area 7,000 m2
Treatment Thickness 3m
Table 2. ORC Advanced Application Details
Application Type Direct Push
Application Rate
Zone 1 WS14 Hotspot
17.01kg/m
Zone 2 Source Treatment
11.34kg/m
Zone 3 Plume Treatment
5.67kg/m
TOTAL MATERIAL COST £130,000
TOTAL PROJECT COST £220,000
Rapid Reduction of Petroleum Hydrocarbons using
ORC Advanced® allows for Redevelopment of Site

2.
Soil removal works were undertaken at the site in October 2008. ORC Advanced treatment in both the source
and plume areas was undertaken in October and November 2008. ORC Advanced was applied using three direct
push injection rigs and a separate mixing and pumping unit. The rods were driven to 6mBGL and the ORC
Advanced was applied over the impacted saturated zone as the rods were slowly withdrawn to 3mBGL. The rigs
completed a total of 813 injection points in 19 drilling days. The dose rates were varied to match the different
contaminant concentrations and conditions encountered across the site (Tables 1 & 2). Vibro‐piling works were
completed across the site at the same time as the ORC Advanced was being applied and were unimpeded by the
direct push rigs.
Results
Following the injection of ORC Advanced, a slight increase in the dissolved phase contaminant concentrations
was observed due to the site disturbance from injection and piling works. Both TPH and PAH concentrations
then rapidly decreased to below the site specific remedial target values and remained low over the monitoring
programme. A 99% reduction in the groundwater concentrations of TPH and PAH was achieved with no
rebound. Monitoring results are presented below for well BH102, which was located on the southern site
boundary, adjacent to Handtrough Creek.
Table 3: Concentrations overtime at location BH102
Contaminant Oct 2007
(Baseline)
ORC Advanced
Injection (Oct 2008)
Dec 2008 Mar 2009 April 2009 May 2009 Aug 2009 Dec 2009 % Reduction
Total TPH
(μg/L)
1,100 1,600 <10 <10 <10 <10 <10 99%
Total PAH
(μg/L)
230 290 5.9 0.23 0.18 <0.1 <0.1 99%
Conclusion
Following the application of ORC Advanced, TPH and PAH concentrations were rapidly reduced and maintained
below the site specific target values without contaminant rebound. The works were completed safely and
efficiently and did not hinder the ongoing construction works occurring simultaneously at the site. The low final
contaminant concentrations and the lack of rebound resulted in regulatory acceptance of the remediation and
development works were completed.
Jacobs
Paul Adams
+44 (0)118 963 5071
Paul.Adams@jacobs.com
www.jacobs.com
Regenesis Ltd
Gareth Leonard
+44 (0) 1833 630411
gleonard@regenesis.com
www.regenesis.com